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| United States Patent |
6,175,805
|
|
Abe
|
January 16, 2001
|
Navigation system
Abstract
To cope with differences in the evaluation depending on the user, or
depending on the situation, by making it possible to alter the evaluation
values used for automatically searching for the route, in a navigation
system, which has a map reproduction means 4 storing segment data such as
the distance and the road type, of the road segment forming a road
network, a RAM 6 for storing the evaluation values corresponding to the
segment data, and a control circuit 1 for searching for the route from a
starting point to a destination, in accordance with a synthetic evaluation
function using, as parameters, the evaluation values stored in the RAM 6,
a setting means 7 is provided for altering the evaluation values stored in
the RAM 6.
| Inventors:
|
Abe; Yuichi (Tottori, JP)
|
| Assignee:
|
Sanyo Electric Co., Ltd. (Osaka-Fu, JP);
Tottori Sanyo Electric Co., Ltd. (Tottori-Ken, JP)
|
| Appl. No.:
|
290490 |
| Filed:
|
April 12, 1999 |
Foreign Application Priority Data
| Apr 22, 1998[JP] | 10-112094 |
| Current U.S. Class: |
701/209; 701/201; 701/207; 701/208; 701/213 |
| Intern'l Class: |
G01C 021/20; G06G 007/78 |
| Field of Search: |
701/200-203,207-210,213-216
|
References Cited
U.S. Patent Documents
| 5684704 | Nov., 1997 | Okazaki | 701/208.
|
| 5862509 | Jan., 1999 | Desai et al. | 701/209.
|
| 5878368 | Mar., 1999 | DeGraaf | 701/209.
|
| 5908464 | Jun., 1999 | Kishigami et al. | 701/208.
|
| Foreign Patent Documents |
| 0 547 548 A1 | Jun., 1993 | EP.
| |
| 0 726 447 A1 | Feb., 1996 | EP.
| |
| 0 703 436 A2 | Mar., 1996 | EP.
| |
| 0 751 376 A2 | Jan., 1997 | EP.
| |
| 0 805 337 A2 | May., 1997 | EP.
| |
| 1-138409 | May., 1989 | JP.
| |
Other References
European Patent Office Communication dated Aug. 31, 1999 (3 pages).
Guzolek, J. and Koch, E. "Real-Time Route Planning in Road Networks",
Vehicle Navigation & Information Systems-Conference Record of Papers
presented at the First Vehicle Navigation and Information Systems
Conference (VNIS'89), Compiled and edited by D.H.M. Reekie, E.R. Case and
J. Tsai.
|
Primary Examiner: Gregory; Bernarr E.
Attorney, Agent or Firm: Akin, Gump, Strauss, Hauer & Feld, L.L.P.
Claims
What is claimed is:
1. A navigation system comprising:
a map reproduction means for storing segment data of the type of the road,
and the distance of the road segment forming a road network,
a memory means for storing evaluation values corresponding to the segment
data,
a route evaluation means for searching for the route from the starting
point to a destination, in accordance with a synthetic evaluation function
based on the segment data and, using as parameters, the evaluation values
stored in said memory means,
input means for inputting values to be used as the evaluation values; and
setting means for altering the evaluation values stored in said memory
means by setting the input values as said evaluation values.
2. The navigation system according to claim 1, wherein said input means
comprises an evaluation value alteration key, and a control circuit
responsive to manipulation of the evaluation value alteration key to alter
the evaluation values stored in said memory means.
3. The navigation system according to claim 1, wherein said segment data
includes the data representing a distance, a road type, and the number of
lanes.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a navigation system for searching for or
determining the route from a starting point to a destination.
Many of the navigation systems commercially available are provided with a
route searching function (see Japanese Patent Kokai Publication No.
01138409). According to this function, when a starting point and a
destination are set by an input means or a current position detecting
means, calculation for synthetic evaluation is made using, as parameters,
the evaluation values of each road segment corresponding to the distance,
the number of lanes, the road type, and the like, and the route with the
best evaluation is displayed. For instance, the evaluation value for the
distance is represented by Kn (Kn=10 when the distance is 10 Km), the
evaluation value for the number of lanes is represented by Nn (Nn=100 for
a road of a single lane, Nn=70 for a road with two lanes, Nn=50 for a road
with three lanes, Nn=40 for a road-with four lanes), and the evaluation
value for the type of the road is represented by Dn (Dn=2 for a highway,
Dn=3 for a national road, Dn=6 for main local road, Dn=24 for other local
loads). n denotes the segment number of each route. The synthetic
evaluation is calculated for each of a plurality of routes from the
starting point to the destination, by
.SIGMA.(Kn.multidot.Nn.multidot.Dn),
and the route having the smallest (best) synthetic evaluation is displayed
being high-lighted.
However, there was a problem in that the evaluation thus determined is not
necessarily optimum depending on the user, or depending on the situation.
For example, some users may take the difference between a two-lane road
and a three-lane road to be more significant. Also when in a hurry, the
merit of the high way is increased, while when one has a plenty of time,
the merit of a high way is not so high. Relying on the same evaluation
under these different situations is therefore not proper.
SUMMARY OF THE INVENTION
The invention has been made in view of the above, and the navigation system
of the invention according to the invention has
a storage medium for storing segment data of the type of the road, and the
distance of the road segment forming a road network,
a memory means for storing evaluation values corresponding to the segment
data, a route search means for searching for the route from the starting
point to a destination, in accordance with a synthetic evaluation function
using, as parameters, the evaluation values stored in said memory means,
and
further comprises
setting means for altering the evaluation-values stored in said memory
means.
The setting means may comprise an evaluation value alteration key, and a
control circuit responsive to manipulation of the evaluation value
alteration key to alter the evaluation values stored in said memory means.
The segment data includes the data representing a distance, a road type,
and the number of lanes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the pertinent parts of the structure of
an embodiment of the invention;
FIG. 2A and FIG. 2B are tables showing evaluation values in the embodiment;
FIG. 3 is a flow chart showing the main operations of the embodiment;
FIG. 4 is a diagram showing a starting point and a destination; and
FIG. 5 is a diagram showing a route used for an example of calculation of
the synthetic evaluation in the embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the invention will now be described with reference to the
drawings. FIG. 1 is a block diagram showing pertinent parts of an
embodiment of the invention. Reference numeral 1 denotes a control
circuit, which operates according to programs stored in ROM 2 to control
the entire system. Reference numeral 3 denotes a GPS (global positioning
system) positing measuring means, which receives electromagnetic wave from
GPS satellites, and measures the current position, and supplies the
measurement data to the control circuit 1.
Reference numeral 4 denotes a map reproduction means, which reads map
information from a CD-ROM in which map information is recorded, and
supplies the map information to the control circuit 1. The map information
is divided into a plurality of block groups, and each block group is
divided into layers of road network, intersections, names of the place,
names of transportation network, such as railroads, and buildings, and the
like. The road network layer is divided into segments at every
intersections. The road segments are classified into high-ways, national
roads, main local roads and other local roads. For each road segment, the
distance, the direction, the time taken to drive, the width of the road,
the number of lanes, and the average intervals of traffic signals, and
other appendant data are stored (Japanese Patent Kokai Publication No.
01138409).
Reference numeral 5 denotes a display means, which displays the map, the
current position and the like under control by the control circuit 1.
Reference numeral 6 denotes a RAM (random access memory), which stores the
data necessary for the operation of the control circuit 1, such as the
current position 61, detected by the GPS measuring means 3, the route
history 62 (starting points, destinations, routes) including the actual
route which the user has run along, and the planned routes set in the
past, and the evaluation values 63 used for the calculation for searching
for the route (see FIG. 2A and FIG. 2B).
Reference numeral 7 denotes an input means, which includes a cursor key 71
for scrolling the screen in eight directions, a return key 72 for causing
the output of data to the control circuit 1, a route setting key 73 for
setting the planned route, and an evaluation value alteration key 74 for
altering the evaluation values.
The main operations of the invention will next be described. FIG. 3 is a
flowchart showing the operation of the control circuit 1. The control
circuit 1 monitors to see whether the evaluation value alteration key 74
has been manipulated, or whether the route setting key 73 has been
manipulated (S1, S2).
When it is found that the evaluation value alteration key 74 has been
manipulated at the step S1, the control circuit 1 causes a screen for
altering the evaluation values for the segment data, such as the number of
lanes, and the types of roads (S3), and causes rewriting in the RAM 6 of
the evaluation values having been altered by the manipulation of the
cursor key 71 and the return key 76 (S4). FIG. 2A and FIG. 2B show an
example of alteration made when the user wants to reach the destination as
early as possible. It is seen that the high ways and the number of lanes
are taken as more significant than with the initial values.
In this way, the evaluation values used for the calculation for the search
can be altered according to the situation or according to the user.
When it is found that the route setting key 73 has been manipulated at the
step S2, the control circuit 1 causes display of a list of the existing
route history stored in the RAM 6, and an icon for newly setting a planned
route (S5). The user then input to indicate whether one of the existing
routes is selected, or the planned route is newly set.
When one of the existing routes is selected ("Y" at S6) the selected route
is displayed (S8).
When the new route is selected ("Y" at S7), a screen for prompting input of
the starting point and the destination is displayed (S9). When the
starting point and the destination are input ("Y" at S10), the evaluation
values for the road segment data such as the number of lanes and the type
of the road are read (S11), and the synthetic evaluation of each route
from the starting point to destination is calculated using the evaluation
values having been read (S12).
The routes for which the evaluation is made are limited to those satisfying
certain conditions. For instance a route including a road segment which is
more than 120 degrees with respect to the direction from the starting
point to destination (i.e., the road segment which leads the user farther
away from the destination) is excluded.
In the calculation of the synthetic evaluation of each route, the
evaluation values of the road segment data of the respective road segments
are multiplied, and summed up. As an example, in the search for a route
from the starting point A to destination B shown in FIG. 4, calculation of
the synthetic evaluation of the route consisting of road segments L1 to
L11 is made. For simplicity of description, only the distance, the number
of lanes, and the type of the roads are used as the road segment data for
the synthetic evaluation. The segment data for the distance, the number of
lanes, and the type of the road of the road segment Ln (n=1 to 11) are
respectively denoted by Kn, Nn and Dn. For instance, L3 is 5 km long, has
two lanes, and is a national road, so that K3=5, N3=50, D3=3, and the
synthetic evaluation of L3 is 5.times.50.times.3=750. The synthetic
evaluation of each of L1 to L11 is determined in this way, and the
synthetic evaluations of all of L1 to L11 are summed up to determine the
synthetic evaluation of the route from A to B (the synthetic
evaluation=.SIGMA.(Kn.times.Nn.times.Dn).
In this way, the synthetic evaluation of each route is calculated (S12),
and the route having the smallest (best) synthetic evaluation is selected
(S13). The selected route and the starting point and the destination are
stored in the RAM 6 as a precedent (S14). The selected route is displayed
with a certain color (S15). The route having been stored as the precedent
can be displayed at the above mentioned step S8 when desired by the user.
In the above embodiment, the synthetic evaluation of the route is
determined based on the distance, the number of lanes, and the road type,
according to
.SIGMA.(Kn.times.Nn.times.Dn).
However, the evaluation may be made on road segment data other than the
distance, the number of lanes and the road type. For instance, the average
running speed, traffic regulations, or average intervals between traffic
signals may be used. The formula used for the determination of the
synthetic evaluation may be other than
.SIGMA.(Kn.times.Nn.times.Dn),
and may be
.SIGMA.(coefficient No. 1.times.Kn+coefficient No. 2.times.Nn+coefficient
No. 3.times.Dn).
This applies to segment data other than Kn, Nn and Dn, and the coefficients
may be altered.
As has been described, according to the invention, the evaluation values
for automatically searching for the route can be altered by the user, so
that it is possible to cope with the difference in the evaluation by the
user, and the difference in the evaluation depending on the situation. For
instance, it is possible to cope with the user who takes the difference
between a two-lane road and a three-lane road significant, and the
situation in which the user is in a hurry so that the merit of a high way
is significant, and a situation in which the user has a plenty of time so
that the merit of a high way is not so high.
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